LAUSR

Abstract In this study, the efficacy of biofloc system was assessed for polyculture Indian major carp, e.g., rohu (Labeo rohita), catla (Catla catla), and mrigal (Cirrihinus mrigala) cultured at varied stocking densities (STD) from 4.28, 8.57, and 12.85 fish m-3 of tank volume. Biofloc system could efficiently remove inorganic nitrogen from culture water and substantially improved the growth parameters of fishes as compared to the control system without the application of biofloc. Among different STDs in biofloc system, water quality and floc formation were noted to be higher with a STD of 4.28 fish m-3 and the average concentration of NH4 – N, NO2 – N and NO3 – N of 0.61 mg L-1, 0.35 mg L-1 and 1.8 mg L-1, respectively was recorded lowest as compared to the other STD. As a result, catla and rohu could achieve a specific growth rate of 1.1 % day-1 and 0.98 % day-1, respectively. However, in the other two STDs, the respective concentrations were noted in the range of acceptable water quality, and the growth rates were satisfactory. It can be concluded that the biofloc system is efficient to culture IMC in polyculture mode amd therefore, can be directly applied in scaled-up culture modules.